Efficient preparation of silver nanoparticles supported on hybrid films and their activity in the oxidation of styrene under microwave irradiation

Hybrid films containing different loadings of silver nanoparticles (0.5, 1 and 2.5 wt.%) have been prepared using a sol–gel method. Three types of materials were prepared in order to compare their properties: Ag nanoparticles (NPs) on hybrid film containing methyltrimethoxysilane (Ag-MeTMS), a similar hybrid material containing both MeTMS and 3-mercaptopropyltrimethoxysilane (MPTMS) as modifier (Ag-MeTMS/MPTMS) and finally a Ag-MeTMS film to which starch was added as modifier/reducing agent (Ag-MeTMS/starch). Characterized materials by TEM showed that, in general, Ag materials had a bimodal particle size distribution, with sizes of 7–8, 12–16 nm as well as some bigger agglomerates (on some of them) of 24–25 nm present at increasing silver loadings. The catalytic properties of the supported Ag NP were investigated in the oxidation of styrene. Ag-MeTMS/MPTMS materials were comparatively more active and selective than Ag-MeTMS or Ag-MeTMS/starch, regardless of the Ag content in the materials, providing high conversions and selectivities to styrene oxide.

Graphical abstractAg nanoparticles supported on hybrid organic–inorganic films were synthesized and their activities were investigated in the oxidation of styrene under microwave irradiation. Materials were found to be differently active and selective depending on the composition of the support and exhibited high activities and selectivities to styrene epoxide under microwave irradiation at mild reaction conditions (<200 °C) and very short times of reaction (<30 min).Figure optionsDownload full-size imageDownload as PowerPoint slide